Consolidate code monitoring low memory kills and OOM kills to MemoryKillsMonitor on ChromeOS.

chrome/browser/browser_process_impl.h

Index: chrome/browser/browser_process_impl.h
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index eb2a9cae4a8ccdfce2b956618a3d79d24df116e6..1d2b2ed6c0ffef7e76ffb924d10516f030400cb6 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -23,6 +23,7 @@
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/lifetime/keep_alive_state_observer.h"
+#include "chrome/browser/memory/memory_kills_monitor.h"
 #include "chrome/common/features.h"
 #include "components/prefs/pref_change_registrar.h"
 #include "extensions/features/features.h"
@@ -346,6 +347,10 @@ class BrowserProcessImpl : public BrowserProcess,
   std::unique_ptr<memory::TabManager> tab_manager_;
 #endif
 
+#if defined(OS_CHROMEOS)

[sky, 2016/11/26 16:49:40]

If this is CHROMEOS specific, how come the include isn't only for chromeos? That
said, AFAICT this member isn't used by BrowserProcessImpl. Can it move to
ChromeBrowserMainPartsChromeos?

[cylee1, 2016/11/29 20:28:40]

You're right. Moved it to ChromeBrowserMainPartsChromeos.
Also only include memory_kills_monitor.[cc.h] in ChromeOS build in BUILD.gn 

+  memory::MemoryKillsMonitor::Handle memory_kills_monitor_handle_;
+#endif  // !defined(OS_ANDROID)
+
   shell_integration::DefaultWebClientState cached_default_web_client_state_;
 
   std::unique_ptr<PhysicalWebDataSource> physical_web_data_source_;